Sabellius
Sabellius,
fl. 215, Christian priest and theologian, b. probably Libya or Egypt. He went to Rome, became the leader of those who accepted the doctrine of modalistic monarchianismmonarchianism[Gr.,=belief in the rule of one], the concept of God that maintains his sole authority even over Christ and the Holy Spirit. Its characteristic tenet, that God the Father and Jesus are one person, was developed in two forms in early Christianity.
..... Click the link for more information. , and was excommunicated by Pope St. Calixtus I in 220. Opposing the orthodox teaching of "essential Trinity," Sabellius advanced the doctrine of the "economic Trinity." God, he held, was one indivisible substance, but with three fundamental activities, or modes, appearing successively as the Father (the creator and lawgiver), as the Son (the redeemer), and as the Holy Spirit (the maker of life and the divine presence within men). The term Sabellianism later was used to include all sorts of speculative ideas that had become attached to the original ideas of Sabellius and his followers. In the East, all monarchians came to be labeled Sabellians.